#include <cstdio>

#include <Bust/Crypting/MD5.hpp>

namespace bust {

const char* MD5::engineName() {
	return "MD5";
}

std::string MD5::convToString( unsigned char *bytes ) {
	char asciihash[33];

	int p = 0;
	for( int i = 0; i < 16; i++ ) {
		sprintf( &asciihash[p], "%02x", bytes[i] );
		p += 2;
	}
	asciihash[32] = '\0';
	return std::string( asciihash );
}

MD5::MD5() {
}

MD5::~MD5() {
}

std::string MD5::getHashFromString( std::string text ) {
	MD5data ctx;

	init( ctx );
	update( ctx, (unsigned char*) text.c_str(), text.length() );

	unsigned char buff[16] = "";
	final( (unsigned char*) buff, ctx );

	return convToString( buff );
}

std::string MD5::getHashFromFile( std::string filename ) {
	FILE *file;
	MD5data context;

	int len;
	unsigned char buffer[1024], digest[16];

	if( ( file = fopen( filename.c_str(), "rb" ) ) == NULL ) {
		return "-1";
	}

	init( context );

	while( ( len = fread( buffer, 1, 1024, file ) ) ) {
		update( context, buffer, len );
	}
	final( digest, context );
	fclose( file );
	return convToString( digest );
}

#define S11 7
#define S12 12
#define S13 17
#define S14 22
#define S21 5
#define S22 9
#define S23 14
#define S24 20
#define S31 4
#define S32 11
#define S33 16
#define S34 23
#define S41 6
#define S42 10
#define S43 15
#define S44 21

static unsigned char PADDING[64] = { 0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
		0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
		0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
		0, 0, 0 };

/* F, G, H and I are basic MD5 functions. */
#define F(x, y, z) (((x) & (y)) | ((~x) & (z)))
#define G(x, y, z) (((x) & (z)) | ((y) & (~z)))
#define H(x, y, z) ((x) ^ (y) ^ (z))
#define I(x, y, z) ((y) ^ ((x) | (~z)))

/* ROTATE_LEFT rotates x left n bits. */
#define ROTATE_LEFT(x, n) (((x) << (n)) | ((x) >> (32-(n))))

/*
 FF, GG, HH, and II transformations for rounds 1, 2, 3, and 4.
 Rotation is separate from addition to prevent recomputation.
 */
#define FF(a, b, c, d, x, s, ac) { \
 (a) += F ((b), (c), (d)) + (x) + (unsigned long int)(ac); \
 (a) = ROTATE_LEFT ((a), (s)); \
 (a) += (b); \
  }

#define GG(a, b, c, d, x, s, ac) { \
 (a) += G ((b), (c), (d)) + (x) + (unsigned long int)(ac); \
 (a) = ROTATE_LEFT ((a), (s)); \
 (a) += (b); \
  }
#define HH(a, b, c, d, x, s, ac) { \
 (a) += H ((b), (c), (d)) + (x) + (unsigned long int)(ac); \
 (a) = ROTATE_LEFT ((a), (s)); \
 (a) += (b); \
  }
#define II(a, b, c, d, x, s, ac) { \
 (a) += I ((b), (c), (d)) + (x) + (unsigned long int)(ac); \
 (a) = ROTATE_LEFT ((a), (s)); \
 (a) += (b); \
  }

void MD5::init( MD5data &context ) {
	context.count[0] = context.count[1] = 0;
	context.state[0] = 0x67452301;
	context.state[1] = 0xefcdab89;
	context.state[2] = 0x98badcfe;
	context.state[3] = 0x10325476;
}

void MD5::update( MD5data &context, unsigned char *input,
		unsigned int inputLen ) {
	unsigned int i, index, partLen;

	index = (unsigned int) ( ( context.count[0] >> 3 ) & 0x3F );

	if( ( context.count[0] += ( (unsigned long int) inputLen << 3 ) )
			< ( (unsigned long int) inputLen << 3 ) )
		context.count[1]++;

	context.count[1] += ( (unsigned long int) inputLen >> 29 );
	partLen = 64 - index;

	if( inputLen >= partLen ) {
		MD5_memcpy( (POINTER) &context.buffer[index], (POINTER) input, partLen );
		transform( context.state, context.buffer );

		for( i = partLen; i + 63 < inputLen; i += 64 )
			transform( context.state, &input[i] );

		index = 0;
	} else
		i = 0;

	MD5_memcpy( (POINTER) &context.buffer[index], (POINTER) &input[i],
			inputLen - i );
}

void MD5::final( unsigned char digest[16], MD5data& context ) {
	unsigned char bits[8];
	unsigned int index, padLen;

	encode( bits, context.count, 8 );

	index = (unsigned int) ( ( context.count[0] >> 3 ) & 0x3f );
	padLen = ( index < 56 ) ? ( 56 - index ) : ( 120 - index );
	update( context, PADDING, padLen );

	update( context, bits, 8 );

	encode( digest, context.state, 16 );

	MD5_memset( (POINTER) &context, 0, sizeof ( context ) );
}

void MD5::transform( unsigned long int state[4],
		unsigned char block[64] ) {
	unsigned long int a = state[0], b = state[1], c = state[2], d = state[3],
			x[16];

	decode( x, block, 64 );

	FF (a, b, c, d, x[ 0], S11, 0xd76aa478);
	FF (d, a, b, c, x[ 1], S12, 0xe8c7b756);
	FF (c, d, a, b, x[ 2], S13, 0x242070db);
	FF (b, c, d, a, x[ 3], S14, 0xc1bdceee);
	FF (a, b, c, d, x[ 4], S11, 0xf57c0faf);
	FF (d, a, b, c, x[ 5], S12, 0x4787c62a);
	FF (c, d, a, b, x[ 6], S13, 0xa8304613);
	FF (b, c, d, a, x[ 7], S14, 0xfd469501);
	FF (a, b, c, d, x[ 8], S11, 0x698098d8);
	FF (d, a, b, c, x[ 9], S12, 0x8b44f7af);
	FF (c, d, a, b, x[10], S13, 0xffff5bb1);
	FF (b, c, d, a, x[11], S14, 0x895cd7be);
	FF (a, b, c, d, x[12], S11, 0x6b901122);
	FF (d, a, b, c, x[13], S12, 0xfd987193);
	FF (c, d, a, b, x[14], S13, 0xa679438e);
	FF (b, c, d, a, x[15], S14, 0x49b40821);

	GG (a, b, c, d, x[ 1], S21, 0xf61e2562);
	GG (d, a, b, c, x[ 6], S22, 0xc040b340);
	GG (c, d, a, b, x[11], S23, 0x265e5a51);
	GG (b, c, d, a, x[ 0], S24, 0xe9b6c7aa);
	GG (a, b, c, d, x[ 5], S21, 0xd62f105d);
	GG (d, a, b, c, x[10], S22, 0x2441453);
	GG (c, d, a, b, x[15], S23, 0xd8a1e681);
	GG (b, c, d, a, x[ 4], S24, 0xe7d3fbc8);
	GG (a, b, c, d, x[ 9], S21, 0x21e1cde6);
	GG (d, a, b, c, x[14], S22, 0xc33707d6);
	GG (c, d, a, b, x[ 3], S23, 0xf4d50d87);

	GG (b, c, d, a, x[ 8], S24, 0x455a14ed);
	GG (a, b, c, d, x[13], S21, 0xa9e3e905);
	GG (d, a, b, c, x[ 2], S22, 0xfcefa3f8);
	GG (c, d, a, b, x[ 7], S23, 0x676f02d9);
	GG (b, c, d, a, x[12], S24, 0x8d2a4c8a);

	HH (a, b, c, d, x[ 5], S31, 0xfffa3942);
	HH (d, a, b, c, x[ 8], S32, 0x8771f681);
	HH (c, d, a, b, x[11], S33, 0x6d9d6122);
	HH (b, c, d, a, x[14], S34, 0xfde5380c);
	HH (a, b, c, d, x[ 1], S31, 0xa4beea44);
	HH (d, a, b, c, x[ 4], S32, 0x4bdecfa9);
	HH (c, d, a, b, x[ 7], S33, 0xf6bb4b60);
	HH (b, c, d, a, x[10], S34, 0xbebfbc70);
	HH (a, b, c, d, x[13], S31, 0x289b7ec6);
	HH (d, a, b, c, x[ 0], S32, 0xeaa127fa);
	HH (c, d, a, b, x[ 3], S33, 0xd4ef3085);
	HH (b, c, d, a, x[ 6], S34, 0x4881d05);
	HH (a, b, c, d, x[ 9], S31, 0xd9d4d039);
	HH (d, a, b, c, x[12], S32, 0xe6db99e5);
	HH (c, d, a, b, x[15], S33, 0x1fa27cf8);
	HH (b, c, d, a, x[ 2], S34, 0xc4ac5665);

	II (a, b, c, d, x[ 0], S41, 0xf4292244);
	II (d, a, b, c, x[ 7], S42, 0x432aff97);
	II (c, d, a, b, x[14], S43, 0xab9423a7);
	II (b, c, d, a, x[ 5], S44, 0xfc93a039);
	II (a, b, c, d, x[12], S41, 0x655b59c3);
	II (d, a, b, c, x[ 3], S42, 0x8f0ccc92);
	II (c, d, a, b, x[10], S43, 0xffeff47d);
	II (b, c, d, a, x[ 1], S44, 0x85845dd1);
	II (a, b, c, d, x[ 8], S41, 0x6fa87e4f);
	II (d, a, b, c, x[15], S42, 0xfe2ce6e0);
	II (c, d, a, b, x[ 6], S43, 0xa3014314);
	II (b, c, d, a, x[13], S44, 0x4e0811a1);
	II (a, b, c, d, x[ 4], S41, 0xf7537e82);
	II (d, a, b, c, x[11], S42, 0xbd3af235);
	II (c, d, a, b, x[ 2], S43, 0x2ad7d2bb);
	II (b, c, d, a, x[ 9], S44, 0xeb86d391);

	state[0] += a;
	state[1] += b;
	state[2] += c;
	state[3] += d;

	MD5_memset( (POINTER) x, 0, sizeof ( x ) );
}

void MD5::encode( unsigned char *output, unsigned long int *input,
		unsigned int len ) {
	unsigned int i, j;

	for( i = 0, j = 0; j < len; i++, j += 4 ) {
		output[j] = (unsigned char) ( input[i] & 0xff );
		output[j + 1] = (unsigned char) ( ( input[i] >> 8 ) & 0xff );
		output[j + 2] = (unsigned char) ( ( input[i] >> 16 ) & 0xff );
		output[j + 3] = (unsigned char) ( ( input[i] >> 24 ) & 0xff );
	}
}

void MD5::decode( unsigned long int *output, unsigned char *input,
		unsigned int len ) {
	unsigned int i, j;

	for( i = 0, j = 0; j < len; i++, j += 4 )
		output[i] = ( (unsigned long int) input[j] )
				| ( ( (unsigned long int) input[j + 1] ) << 8 )
				| ( ( (unsigned long int) input[j + 2] ) << 16 )
				| ( ( (unsigned long int) input[j + 3] ) << 24 );
}

void MD5::MD5_memcpy( POINTER output, POINTER input,
		unsigned int len ) {
	unsigned int i;

	for( i = 0; i < len; i++ )
		output[i] = input[i];
}

void MD5::MD5_memset( POINTER output, int value, unsigned int len ) {
	unsigned int i;
	for( i = 0; i < len; i++ )
		( (char *) output )[i] = (char) value;
}

}
